There are several UK species of this versatile tree – Goat willow, Crack willow, Bay willow, Grey willow, White willow…. And many of these are suited to wet, boggy ground. Crack willow – aptly known scientifically as Salix fragilis – does particularly well along the riverbank. As the name suggests, branches and twigs often break off – with a crack – wash downstream, and root into the bank where they rest. This ease of rooting from cuttings, its flexibility and speed of growth makes willow an excellent material for building green bank protection.
While erosion is a natural and positive river process, excessive erosion can cause siltation of the river and threaten infrastructure or farmland. Where this is the case, willow can be used – often along with other materials – to create robust, long-lasting and environmentally positive bank protection. We have tested several methods including willow weaving, brash banking, willow pegs, laying out rods on reprofiled banks and combinations of the above.
It is a fantastic material to work with, produces results fast and is very palatable to our native grazers while being fairly resilient to browsing. This makes willow a must have in post-beaver-reintroduction Scotland.
The downside is that, once established, willow could over shade rivers and, therefore, will require some maintenance; but the beavers will see to that.